/// <summary>
/// returns a parameter t such that the distance between curve[t] and targetPoint is minimal
/// and t belongs to the closed segment [low,high]
/// </summary>
/// <param name="targetPoint">the point to find the closest point</param>
/// <param name="high">the upper bound of the parameter</param>
/// <param name="low">the low bound of the parameter</param>
/// <returns></returns>
public double ClosestParameterWithinBounds(Point targetPoint, double low, double high)
{
const int numberOfTestPoints = 8;
double t = (high - low) / (numberOfTestPoints + 1);
double closest = low;
double minDist = Double.MaxValue;
for (int i = 0; i <= numberOfTestPoints; i++)
{
double par = low + i * t;
Point p = targetPoint - this[par];
double d = p * p;
if (d < minDist)
{
minDist = d;
closest = par;
}
}
if (closest == 0 && high == Math.PI * 2)
{
low = -Math.PI;
}
double ret = ClosestPointOnCurve.ClosestPoint(this, targetPoint, closest, low, high);
if (ret < 0)
{
ret += 2 * Math.PI;
}
return(ret);
}
/// <summary>
/// returns a parameter t such that the distance between curve[t] and a is minimal
/// </summary>
/// <param name="targetPoint"></param>
/// <returns></returns>
public double ClosestParameter(Point targetPoint)
{
double t = 1.0 / 8;
double closest = 0;
double minDist = Double.MaxValue;
for (int i = 0; i < 9; i++)
{
Point p = targetPoint - this[i * t];
double d = p * p;
if (d < minDist)
{
minDist = d;
closest = i * t;
}
}
return(ClosestPointOnCurve.ClosestPoint(this, targetPoint, closest, 0, 1));
}
/// <summary>
/// returns a parameter t such that the distance between curve[t] and targetPoint is minimal
/// and t belongs to the closed segment [low,high]
/// </summary>
/// <param name="targetPoint">the point to find the closest point</param>
/// <param name="high">the upper bound of the parameter</param>
/// <param name="low">the low bound of the parameter</param>
/// <returns></returns>
public double ClosestParameterWithinBounds(Point targetPoint, double low, double high)
{
System.Diagnostics.Debug.Assert(high <= 1 && low >= 0);
System.Diagnostics.Debug.Assert(low <= high);
double t = (high - low) / 8;
double closest = 0;
double minDist = Double.MaxValue;
for (int i = 0; i < 9; i++)
{
Point p = targetPoint - this[i * t + low];
double d = p * p;
if (d < minDist)
{
minDist = d;
closest = i * t + low;
}
}
return(ClosestPointOnCurve.ClosestPoint(this, targetPoint, closest, low, high));
}
/// <summary>
/// returns a parameter t such that the distance between curve[t] and a is minimal
/// </summary>
/// <param name="targetPoint"></param>
/// <returns>the parameter of the closest point</returns>
public double ClosestParameter(Point targetPoint)
{
double savedParStart = 0;
const int numberOfTestPoints = 8;
double t = (ParEnd - ParStart) / (numberOfTestPoints + 1);
double closest = ParStart;
double minDist = Double.MaxValue;
for (int i = 0; i <= numberOfTestPoints; i++)
{
double par = ParStart + i * t;
Point p = targetPoint - this[par];
double d = p * p;
if (d < minDist)
{
minDist = d;
closest = par;
}
}
bool parStartWasChanged = false;
if (closest == 0 && ParEnd == Math.PI * 2)
{
parStartWasChanged = true;
savedParStart = ParStart;
ParStart = -Math.PI;
}
double ret = ClosestPointOnCurve.ClosestPoint(this, targetPoint, closest, ParStart, ParEnd);
if (ret < 0)
{
ret += 2 * Math.PI;
}
if (parStartWasChanged)
{
ParStart = savedParStart;
}
return(ret);
}
